RuntimeError: failed to connect to server

[mkspeakman]

When running the python script, I get this result.
Forgive my ignorance, but I don't know the cause of the error below.
Can you assist?

python airprint-generate.py

Traceback (most recent call last):
File "airprint-generate.py", line 277, in
apg.generate()
File "airprint-generate.py", line 116, in generate
conn = cups.Connection()
RuntimeError: failed to connect to server